Air conditioning system



Sept. 23, 1958 R. A. STURLEY 2,353,275

AIR CONDITIONING SYSTEM Filed Oct. 1. 1954 2 Sheets-Shet 1 FIG. I

INVENTOR. RICHARD A. STURLEY WMSM ATTORNEY FIG. 3 BY R. A. STURLEY AIR CONDITIONING SYSTEM 2 Sheets-Sheet 2 INVENTOR. RICHARD A. STURLEY ATTORNEY Sept. 23, 1958 Filed Oct. 1. 1954 FIG. 4

United States Patent AIR CONDITIONING SYSTEM Richard A. Sturley, Kirkville, N. Y., assignor to Carrier Corporation syracuse, N. Y., a corporation of Delaware Application October 1, 1954, Serial No. 459,688 9 Claims. (Cl. 257-9) This invention relates generally to air conditioning apparatus of the type that may be used in an enclosure such as a residential home or the like to produce either a cooling effect or a heating effect to function as a unit capable of operation throughout the year in areas having extreme temperature variations. More specifically this invention relates to apparatus of the kind described utilizing the conventional absorption refrigeration cycle to produce the desired thermal effects.

Still more specifically this invention relates to air conditioning systems including a refrigeration system of the absorption type wherein a cooling action is effected by evaporating refrigerant such as water in the evaporator and a heating action is eifectedby passing refrigerant in the vapor phase to the evaporator coil where it may condense when passed in heat exchange relation with the medium to be heated. The invention contemplates an arrangement for use with the condenser of the refrigeration system for ensuring adequate passage of vapor to the evaporator when heating is required, it being understood that the volume of refrigerant in the vapor phase necessary to maintain comfortable heating in an enclosure is much greater than the volume of refrigerant in the liquid phase necessary to achieve comfortable cooling.

In systems of the type under consideration the flow of coolant, usually water to the condenser cooling coil is regulated by a control including a seasonal operating switch. When, for illustration, there is a requirement for heating, as during the winter, the flow of coolant to the condenser cooling coil is prevented so that condensation of the vapor from the generator does not occur in the condenser but rather the vapor flows to the evaporator where it is passed in heat exchange relation with the air under the influence of a fan. The heat contained in the vapor is transferred to the air causing condensation of the vaporous refrigerant in the evaporator. On the other hand, when cooling is required the normal flow of coolant is permitted so that condensation of the vaporous refrigerant in the condenser occurs and liquid refrigerant is introduced into the evaporator to be vaporized therein as heat is absorbed from air being passed in heat exchange relation therewith. In accordance with the present invention it is contemplated that two lines, one larger in relation .to the other be provided to connect the evaporator and the condenser because of the volume relationship mentioned above. Therefore, there is provided a line having a relatively large diameter and a line having a relatively small diameter connecting the condenser and the evaporator. When a heating action is required vapor is free to flow through the larger line or both lines and under cooling conditions liquid refrigerant flows from the condenser to the evaporator through the smaller line, the larger line being closed by a valve arrangement forming one of the features of the invention.

It is therefore the chief object of this invention to provide an arrangement for selectively controlling the effective passageway between the condenser and the evaporator so that vaporous refrigerant in an amount suf- 2,853,275 Patented Sept. 23, 1958 ficient to promote comfortable conditions within the enclosure, being serviced by the system, will be permitted to pass to the evaporator when a demand for heating is made on the system and the conditions, including the proper system pressure differential, necessary to effect vaporization of liquid refrigerant during the cooling cycle will remain undisturbed.

It is a further object of this invention to provide an arrangement in the form of a valve automatically operable in response to a predetermined amount of condensate formed in the condenser for blocking the larger of two lines connecting the condenser and the evaporator. This of course limits the passage of refrigerant to the evaporator through the smaller line which is provided with a pressure seal so as to create the necessary pressure differential between the condenser and evaporator for vaporizing liquid refrigerant.

Another object of the invention is an arrangement of the type described that is automatically operable in response to a shift in a seasonal operating control so as to be utilized under circumstances where the system is hermetically sealed.

Other objects and advantages will be apparent from a consideration of the ensuing specification and drawings in which:

Figure l is a schematic view of an absorption refrigeration system equipped with means permitting operation of the system for both heating and cooling in accordance with my invention;

Figure 2 is a view partly in section showing the condenser of the absorption refrigeration system equipped with a valve permitting the system to be used for both heating and cooling;

Figure 3 is a view similar to Figure 2 showing a modification of the valve member; and

Figure 4 is-a view similar-to Figure 3 showing a further modification of the valve member.

Onetype of a heating and cooling installation in which this invention may be used involves a system wherein the evaporator coil of an absorption refrigeration system is used to heat as well as cool an enclosure such as a small home or the like. In such an installation .the' absorption refrigeration system includes the usual components such as a generator, a condenser, an absorber as well as the evaporator. As more particularly shown in Figure 1 a. pump 2 feeds weak solution of a refrigerant, such as, water and an absorbent, .such as a lithium bromide solution, from the absorber 3 to a heat exchanger 4 through lines 5 and 5a from where it flows to the generator 6 through line 7. The term weak solution is used to designate a solution relatively rich in refrigerant so that the absorbing properties of the solution are poor. The term strong solution as hereinafter used refers to a solution deficient in refrigerant so that the absorbing properties of the solution are good.

In the generator the solution is heated with the vaporous refrigerant passing to the condenser 8 through line 9 and the strong solution flowing through line 10 to the heat exchanger 4 where it warms the Weak solution passing to the generator. From the heat exchanger 4 the strong solution flows through line 10a to the absorber 3. The refrigerant in vapor form is condensed through the action of the coil in the condenser and passes to the evaporator 11 through line 811 where normally it is evaporated and passes in vapor form through line 12 to the absorber where it is absorbed by strong solution from the heat exchanger to form the weak solution.

At this point the pump 2 feeds the weak solution to the heat exchanger and the cycle is repeated. Line 8a is provided with a looped portion forming a pressure seal between the condenser and evaporator so that the evaporator is maintained at a pressure sufficient to cause va- 3 porization of the liquid refrigerant when it is passed in heat exchange relation with the ambient air.

As pointed out above, it is desirable that the evaporator in this particular installation serve as a heating unit under certain circumstances. One particular problem to overcome in order to use the system as desired involves an arrangement which must pass a considerable volume of vaporous refrigerant as compared to the volume of liquid refrigerant if an adequate heating condition is to be achieved. One solution to this problem includes the structural arrangement of the two lines 8a and 20 connecting the condenser and evaporator. The line 20 is of a greater diameter than the line 8a and is used to provide a path of flow for the refrigerant in vapor form to the evaporator when the heating effect is required. During this latter phase of operation, pressure throughout the system is substantially constant, and vapor passes from the generator through the condenser to the evaporator where it is condensed when passed in heat exchange relation with the air in the enclosure.

The condenser coolant is inactive during this phase of operation, permitting the vapor to flow into the evaporator. It will be understood that the flow of coolant in the condenser will be regulated by a cooling tower pump 17 under the influence of a suitable control. A circuit for the condenser and absorber coolant includes line 14 carrying water from a cooling tower (not shown) through a coil A in the condenser, through line 15 to the cooling coil B in the absorber, from where it flows through l ne 16 to the cooling tower pump 17.

As pointed out above when there is a requirement for cooling made on the system. then it is necessary that a pressure differential exist between the absorber and evaporator and the rest of the system. The pressure differential is maintained bv the solution pump and the liquid seal obtained throu h the use of the looped line So and a valve 23, automatically responsive to the operation of the cooling cycle. for preventing communication between the condenser and the vapor accommodating line 20.

Mounted above the juncture of line 20 and the condenser is a cup-like valve 23. The valve is connected to an arm having one end keyed to shaft 24 supported in spaced brackets 22. The valve is maintained in spaced relation to the opening communicating with line 20 through the action of the counterweight 26 connected to arm 27 which in turn has one end keyed to the shaft 24. The parts are so arranged that the cup 23 receives condensate that forms on the surface of the condenser coil and drips downwardly. After an amount of condensate sufiicient to overcome the action of the counterweight has accumulated within the cup, the cup is forced downwardly so as to seat in the opening formed by the juncture of line 20 with the base of the condenser and prevent communication between line 20 and the condenser. The liquid condensate then flows on to the evaporator through line 8a and is vaporized therein to provide the required cooling effect.

Considering the operation of the system as equipped with a valve of the type illustrated in Figure 2, there is normally provided a control, for the operation of the system, which includes a summer-winter operating switch 50, which switch in one instance completes a circuit through the cooling tower pump so that flow of coolant through the condenser coil causes the condenser to function in its intended manner and change the vaporous refrigerant to the liquid phase for subsequent vaporization in the evaporator and in the other instance maintains the circuit through the cooling tower pump open so that the condensation referred to above does not occur and the vaporous refrigerant passes from the generator to the evaporator for condensation therein.

Under the conditions outlined above the coolant passes to the coil in the condenser when a cooling effect is desired, such as desired in the summer months, as .the

switch is shifted to the summer operating position. It will be obvious that other control schemes may be employed with the construction disclosed, however, I prefer to use the control system, of which the seasonal operating switch is a component, disclosed in copending application Serial No. 459,657 filed October 1, 1954 in the names of Richard Merrick and Everett Palmatier.

Assuming that the absorption system has been shut down, through the operation of a thermostat, after having operated under winter operating conditions wherein the system has been used to create a heating effect through heat transfer between ambient air and vaporous refrigerant in the evaporator coil, and that it is desired to operate the system so as to produce a cooling effect, the switch is shifted to the summer operating position whereby a circuit is completed through the cooling tower pump and a second circuit (not shown), is energized to activate the refrigeration cycle. The system is then caused to function in its normal intended manner with coolant flowing to the cooling coil in the condenser.

The vaporous refrigerant is condensed, in part, on the condenser coil from where the condensate drips into the cup-shaped valve 23 until an accumulation in excess of that necessary to overcome the action of the counterweight occurs. Thus the large line 20 is blocked and an eflicient seal created as the action of the pump causes a pressure differential to exist on the opposed sides of the valve 23. The cooling action resulting from the vaporization of the liquid refrigerant in the evaporator continues until a thermostat operable in response to a minimum temperature within the enclosure opens the circuit.

In the event it is desired to operate the system on the heating cycle as for example, during the winter months, the control operates to prevent the fiow of coolant through the condenser coil when the seasonal switch is opened or shifted to the winter operating position. The temperature within the condenser rises and eventually causes the vaporization of the condensate in the member 23. This action permits the counterweight to cause the cup to assume the position shown in Figure 2 so that vapor passes unrestricted to the evaporator through lines 8a and 20. Conventional fans assist in distributing air within the enclosure in heat exchange relation with the evaporator to ensure efficiency in the operation of the system.

When the vapor passes directly from the condenser to the evaporator it condenses and gravitates to the bottom of the evaporator. From the evaporator the vapor or condensate flows through line 22 to the absorber where it mixes with strong solution in the conventional manner.

Another embodiment of the invention is shown in Figure 3 wherein the ends of lines 54 and 56 extend above the base of the condenser 34. When a demand for cooling is made on the system, the condensate, available because of the increased condensation action, collects in the condenser. Pivotaly mounted rod 29 has aflixed to one end a cover plate 28 and to the other end a float 30. As the level of the condensate rises in the condenser the float causes rod 29 to pivot about shaft 31 mounted between spaced brackets 32. The cover 28 moves to a position covering the open end of line 54. When the demand for heating occurs, the temperature within the condenser rises, causes evaporation of the condensate and subsequent descent of float 30 so that the vapor may pass through line 54 as the cover plate 28 moves upwardly.

If desired the invention may be used in the manner shown in Figure 4 wherein a separate receiver 40 is provided between the condenser 35 and evaporator (not shown). The receiver communicates with the condenser through line 43.

Condensate from the condenser passes into the cup 41 which is mounted in the manner illustrated in Figure 1. When an amount of condensate sufiicient to overcome the action of the counterweight 42 collects in the cup, passage of liquid through line 20 is prevented. The conthe condenser and evaporator.

densate within the cup is flashed off when vapor passes through the condenser in response to a demand for heatmg.

In conclusion it will be obvious that with the aid of the invention here involved, a conventional absorption refrigeration system may be effectively utilized for either heating or cooling an enclosure without the necessity of employing manually operated valves in the lines between It will also be obvious that other forms of valves may be used to control the flow of refrigerant through the large line connecting the condenser and evaporator, without exceeding the scope of this invention. Further it will be evident that a valve mechanism is shown which is automatically operable to a shift in the control system from the summer or cooling operation to the winter or heating operation and vice versa.

I claim:

1. An absorption refrigeration system comprising an absorber, a generatona line connecting the absorber and the generator, a pump in the line for transmitting solution from the absorber to the generator, a condenser, cooling means in the condenser, a line connecting the generator and the condenser, an evaporator, two lines connecting the evaporator and the condenser, a line connecting the evaporator and the absorber, means controlling the operation of the condenser cooling means, and means operable in response to the presence of condensate within the condenser for restricting passage of refrigerant from the condenser to the evaporator to one of the two lines.

2. The arrangement set forth in claim 1 wherein said last mentioned means includes a valve having a first position remote from the two lines and a second position obstructing one of the said lines.

3. The arrangement set forth in claim 1 wherein said last mentioned means includes a hollow semi-spheroid adapted to close one of the said lines in response to' the accumulation in the spheroid of a predetermined amount of condensate.

4. The arrangement set forth in claim 3 wherein means are provided to urge said hollow semi-spheroid to a position permittig unrestricted passage of refrigerant in vapor form to the evaporator through one of said lines.

5. The arrangement set forth in claim 4 wherein said semi-spheroid is positioned in said condenser to receive condensate dripping from the cooling coil in an amount sufficient to overcome the action of said urging means and close one of the said lines.

6. In air conditioning apparatus including an absorption refrigeration system, an evaporator, a condenser, a first line connecting the evaporator and the condenser, a second line having a cross-sectional area in excess of the cross-sectional area of the first line connecting the evaporator and the condenser, cooling means within the condenser, means controlling operation of the cooling means, and means operable in response to the accumulation of condensate prior to its passage to the evaporator for restricting passage of refrigerant from the condenser to the evaporator to the line having the smallest crosssectional area.

7. The arrangement as set forth in claim 6 wherein the line having the smaller cross-sectional area is provided with a looped portion intermediate thereof forming a liquid seal between the condenser and the evaporator.

8. In an air conditioning system including a condenser, a cooling coil within the condenser and an evaporator, a control for regulating the flow of coolant in the cooling coil, two lines connecting the condenser and the evaporator for transmitting either vaporous or liquid refrigerant to the evaporator, and means including a valve member mounted in the condenser for movement across one of the openings defined by one of the lines to restrict passage of refrigerant therethrough when refrigerant in liquid form is being transmitted to the evaporator.

9. In an air conditioning system including a condenser, cooling means within the condenser, and an evaporator, a control for regulating flow of coolant within the cooling means, conduit means defining two paths of flow and connecting the condenser and the evaporator for transmitting either vaporous or liquid refrigerant to the evaporator, and means including a valve member governing the effective capacity of one of said paths of flow, said means being operative in response to presence of a predetermined supply of liquid refrigerant formed in the condenser to restrict the capacity of said one of said paths of flow, said means further being operative in response to a supply of liquid refrigerant less than said predetermined supply to increase the capacity of said one of said paths of flow.

References Cited in the file of this patent UNITED STATES PATENTS 1,506,530 Kasley Aug. 26, 1924 2,148,571 Meyerhoefer Feb. 28, 1939 2,461,513 Berestneff Feb. 15, 1949 2,557,573 Sherwood June 19, 1951 

